In the field of orthopedic surgery, several types of apparatus are known for correction, support or other treatment of tissues. For example, in the spinal field, elongated support members such as rods, bars or plates are connected to vertebrae or adjacent tissue so as to provide a corrected spinal curvature, for support of injured or surgically-treated vertebrae or vertebral joints, and for other purposes. Such elongated members can be connected to bone, for example, via a variety of implants including screws, bolts, clamps, wires, hooks.
In some surgical cases, it may be desired to have the elongated member positioned at different heights from bone or other tissue, or have the ability to adjust the positioning of the elongated member or a piece that holds it with respect to a screw, hook or other apparatus. The surgical therapy, the size of the patient and/or the anatomy to be operated on may require variability of placement and/or adjustment of implants with respect to elongated members.